1995 Signature Rookies
 

Is there a way to tell if a signed one was one of the officially signed ones or just one that was issued without a signature and had one added later?

Please show an example. It looks like the print run and hand- numbering are a way to tell them apart.
"1 of 38,000" - unsigned.
"4109 of 7,750" - signed.

You could also check TCDB. That may answer your question.

I've never been able to figure out how to upload an image here, but I can email some examples if you don't mind giving me your email address.

Upload them to a file sharing service like imgur, then post the link.

The numbering in the foil and the hand numbering are the obvious ones.

I'm trying to remember if I have any signature rookies from any set other than the 8x10s that aren't hand numbered. Maybe one of the tv shopping set bonus cards?

If they're basic set cards, or their inserts, they'll be hand numbered.

A few bonus cards have a SR sticker on the back.